With diversification of foods in recent years, various packaging materials have been proposed. Above all, containers having easy peel properties are widely used as those for instant noodles, yogurt, confectionery and other foods. Sealant films having easy peel properties are required to simultaneously satisfy sealing properties and easy peel properties which are conflicting with each other. Further, with diversification of food containers, development of sealant films having various heat-sealing strengths has been desired. On the other hand, from the viewpoints of prevention of contamination of the contents and appearance of merchandise, it is required that not only peel traces (angel hair resin) should not remain when the sealed surface is peeled but also the angel hair (nappy phenomenon) per se should not take place.
In Japanese Patent Laid-Open Publication No. 337829/1998, an easy-peelable film formed from low-density polyethylene and polybutene-1 is disclosed. By changing the amount of the polybutene-1 added, control of the sealing strength is possible, but there is a problem that angel hair (nappy phenomenon) takes place by the increase of the amount of polybutene-1.